Integral image elements which align a lenticular or fly's eye lens sheet with a two dimensional image to create a three dimensional effect are known. A lenticular lens sheet has a plurality of narrow, parallel, elongated and partially cylindrical lenses, and a "fly's eye" lens sheet has a plurality of small lenses arranged in rows and columns on the sheet. Such imaging elements and their construction, are described in "Three-Dimensional Imaging Techniques" by Takanori Okoshi, Academic Press, Inc., New York, 1976. Integral image elements having a lenticular lens sheet are also described in the following U.S. Pat. Nos. 5,391,254; 5,424,533; 5,241,608; 5,455,689; 5,276,478; 5,391,254; and 5,424,533. Use of barrier viewing sheets having alternating opaque and transparent lines, instead of a lenticular lens sheet, is also well known.
Integral image elements with lenticular lens sheets use interlaced vertical image slices, which are aligned with the lenticules, so that a three-dimensional image is viewable when the lenticules are vertically oriented with respect to a viewer's eyes. Similar integral image elements, such as described in U.S. Pat. Nos. 3,268,238 and U.S. 3,538,632, can be used to convey a number of individual two-dimensional scenes such as unrelated scenes or a sequence of scenes depicting motion. Such elements, when tilted through a range of angles with respect to a viewer's eyes, can display unrelated images or a sequence of images depicting motion.
Integral image elements using reflective layers behind the integral image to enhance viewing of the integral image by reflected light, are also described in U.S. Pat. Nos. 3,751,258; 2,500,511; 2,039,648, U.S. 1,918,705 and GB 492,186.
Typically to assemble a lenticular integral image element, an original negative is exposed from stored digitized data of a composite lenticular image on a film writer. A suitable negative exposure technique is disclosed in U.S. Pat. No. 5,276,478. After photographic processing, the negative is printed, typically by a projection enlarger, onto a suitable film or paper based photographic print stock. After processing, the lenticular composite print is coated with adhesive, aligned with a lenticular lens sheet, and pressed against the lens sheet to permanently adhere to it in proper registration with the printed lenticular composite image. It is also known to write the lenticular image directly on the a back side of a lenticular lens sheet which is coated with a suitable receiving layer, as disclosed in U.S. Pat. No. 5,349,419 and U.S. 5,279,912. The lenticular image may be temporary, as in a display produced on a cathode ray tube (CRT) or liquid crystal display (LCD) screen on the back side of a lenticular lens sheet.
One difficulty with lenticular images occurs when the observer tries to display a series of images embedded in an integral image at an appropriate frame rate. This becomes obvious in the case of a motion sequence. In order to get a good motion rendering, the lenticular image has to be tilted by the observer at the original frame rate, so that the images are not displayed too slowly nor too fast.
The problem becomes even more critical in the case of an integral image display, containing a series of images to be viewed at different frame rates. In this case, the frame sampling of the motion sequence was not done on a continuous basis but according to the action content of the scene. When rapid action takes place in the scene, the frame sampling rate is increased.
Thus, it is an object of the invention to provide a mechanism that can be used to automatically control and vary the speed of the motion of the integral image element to display the embedded images at an appropriate frame rate and to provide automatic control of other preferred display parameters.